If you want something that looks like it came from Apple however, check out the iMacompanion. It is a single USB 3 port that carries the power and speed of the iMac’s USB 3 (also USB 2 compatible for older models) to the base of your iMac. It has a flat USB cord that will snake under your iMac and to the back USB port. All the instructions you need are in the following graphic and a 15% off offer follows:

The big thing here is the quality: the housing is 100% aluminum and it is designed to fit perfectly onto your iMac. Wiplabs is giving 9to5Toys readers a 15% discount when bought through Amazonusing code 9to5Toys at checkout which knocks it down to $34 with $4.50 shipping (offer is good for a week)